What is a Performa 450 Demo Unit and what is this weird layout/component?

[jajan547]

So I picked up this Performa 450 (Lciii) and it has the words "DEMO UNIT" in the case (pictures below). I also noticed the board is slightly different than that of your typical Lciii/Performa 450 U38 is completely gone it's normally a blank space for a chip but on this board there's no blank space or spot for whatever chip that would've been, instead you see this strange chip, I have no idea what it does but the machine boots just fine. I have managed to find a picture of one other board with the G1 area left blank which is the same as this board except that this board actually has those components present. If you have any ideas please let me know, the serial number isn't even recognized on the Mac serial number decoders I've managed to go to. I also find the "DEMO UNIT" on the case quite odd as the rest seems like a typical case for these machines. Thanks for looking and any comments or feedback is appreciated.

PICTURES BELOW

 

[Powerbase]

I have a Powermac 6500 225 motherboard with some reworking like this. I think its just a quick fix after theyve already made a bunch of boards and found an issue.

 

[jajan547]

I understand very bizarre but then why the weird case?

 

[jajan547]

I understand very bizarre but then why the weird case?

Says DEMO UNIT

 

[Fizzbinn]

I understand very bizarre but then why the weird case?

Sorry, but what is weird about the case?

The Demo Unit marking and motherboard with bodge wires seems to indicate its an early unit used for demo-ing? Demo to exactly who might be the question.

 

[jajan547]

Sorry, but what is weird about the case?

The Demo Unit marking and motherboard with bodge wires seems to indicate its an early unit used for demo-ing? Demo to exactly who might be the question.

Yeah that's what IU mean everything else is normal, what would it be for or why is it marked this way never seen one like this?

 

[jajan547]

What on earth does that little chip do?

 

[Powerbase]

What on earth does that little chip do?

Clock generator, i assume. No markings that i can see, to look up.

 

[jajan547]

I think I see a Foxconn logo not sure though.

 

[joshc]

Says DEMO UNIT

I'm almost certain that's something that was added after it came out the factory, not an Apple sticker/marking. Could've been a demo unit at a reseller or other computer store perhaps. Otherwise the case looks completely normal/stock.

Probably just an earlier board revision. Logic boards tended to go through a couple of revisions, and factory bodges like that with a few wires soldered on top of the board were not uncommon.

U32 is on the bomarc schematics for the LC III, on the same page as the DRAM address stuff and U32 is connected to an ASIC nearby and also the Egret.

 

[Plasticoat]

I have one of these units, exactly the same , I will post a pic later after work.

 

[jajan547]

I have one of these units, exactly the same , I will post a pic later after work.

would love to see.

 

[jajan547]

I'm almost certain that's something that was added after it came out the factory, not an Apple sticker/marking. Could've been a demo unit at a reseller or other computer store perhaps. Otherwise the case looks completely normal/stock.

Probably just an earlier board revision. Logic boards tended to go through a couple of revisions, and factory bodges like that with a few wires soldered on top of the board were not uncommon.

U32 is on the bomarc schematics for the LC III, on the same page as the DRAM address stuff and U32 is connected to an ASIC nearby and also the Egret.

Any idea what chip they soldered these little bodges to, just curious?

 

[Plasticoat]

I’m afraid I have no idea, mission was to recap, and maybe remove wire from egret, and see if it still functions. I think at this point I will leave as it is.

 

[jajan547]

I’m afraid I have no idea, mission was to recap, and maybe remove wire from egret, and see if it still functions. I think at this point I will leave as it is.

Try it out for me and let me know.

 

[joshc]

@max1zzz worked on a new logicboard for these so he might know the part used there.

 

[MrFahrenheit]

For the LC3, there are at least two versions that exist

The early release LC3 boards have a missing chip, and a horrendous bodge wire fix.

I have several boards like the one you picture.

 

[rplacd]

For the LC3, there are at least two versions that exist

The early release LC3 boards have a missing chip, and a horrendous bodge wire fix.

I have several boards like the one you picture.

...how many LC-class Macs did you end up accumulating in your quest to achieve soldering perfection, anyway?

 

[MrFahrenheit]

...how many LC-class Macs did you end up accumulating in your quest to achieve soldering perfection, anyway?

A lot. I got obsessed with buying a non-working machine for $50 so I could save it and make it work. So far I succeeded in saving nearly everything I bought.

Of the beige Mac’s, I believe my last count showed:

Plus:2 (one is my first Mac ever, from 1990)
Classic :1
Classic II: 3
Se: 2
SE/30: 2 or 3
LC/LC2:35 (plus 2x PVT prototypes)
LC3:15
II:1
IIci:6
IIcx:4 (Plus one prototype)
IIsi:4
IIvi/VX: 3
IIfx: 2
475/Q605:19
Mystic: 1
CC2: 1
Q610: 2
Q650: 4
Q700: 1
Q800: 2
6100/60 and /66: 5-6
7100/66 and /80: 2
8600: 3
Beige G3 DT: 2

Apple IIe PDS cards resurrected: 12

Here are some of them (that easily fit in one photo)

 

[jajan547]

A lot. I got obsessed with buying a non-working machine for $50 so I could save it and make it work. So far I succeeded in saving nearly everything I bought.

Of the beige Mac’s, I believe my last count showed:

Plus:2 (one is my first Mac ever, from 1990)
Classic :1
Classic II: 3
Se: 2
SE/30: 2 or 3
LC/LC2:35 (plus 2x PVT prototypes)
LC3:15
II:1
IIci:6
IIcx:4 (Plus one prototype)
IIsi:4
IIvi/VX: 3
IIfx: 2
475/Q605:19
Mystic: 1
CC2: 1
Q610: 2
Q650: 4
Q700: 1
Q800: 2
6100/60 and /66: 5-6
7100/66 and /80: 2
8600: 3
Beige G3 DT: 2

Apple IIe PDS cards resurrected: 12

Here are some of them (that easily fit in one photo)
View attachment 40816

Now that is a collection